Delivering Global Content with CDNs
CDNs are networks of servers spread around the world. They bring copies of your content closer to users, so pages load faster even when visitors are far from your origin.
How they work: edge servers cache static assets like images, CSS, and JavaScript. When a user requests content, the CDN serves it from the nearest edge server. If the item isn’t cached, it fetches it from your origin and stores a copy for next time.
Cache control and TTL matter. Set expiration headers so browsers and the CDN know when to refresh. Use versioned file names for big updates and purge the old content from the edge when needed. Also consider stale-while-revalidate rules if supported.
Dynamic content can also benefit. Many CDNs offer edge logic, smart routing, and even small computations at the edge. For sensitive data, use signed URLs, short TTLs, or bypass caching for login pages or API endpoints.
Benefits include faster load times, less origin load, higher availability, and built-in security like TLS termination and DDoS protection. They also help you scale to large audiences without paying for more servers.
Getting started is simple: pick a CDN, map your domain, and enable caching for static assets. Configure cache headers for your assets, and ensure your site serves assets from the CDN domain. Use HTTP/2 or HTTP/3 for multiplexing, and test from multiple regions to spot hot spots.
Example scenario: a blog that serves images, CSS, and a hero video. Put files under /assets and /images, set cache TTLs of days for images, hours for CSS/JS, and a shorter or dynamic TTL for video if needed. Monitor cache hit rates and latency to refine rules as traffic grows.
Key Takeaways
- CDNs bring content closer to users to reduce latency.
- Proper cache headers and TTLs maximize performance and freshness.
- Test across regions and monitor cache metrics to keep your site fast worldwide.